Apparatus for wireless signaling.



R. A. fissENDBN. APPARATUS FOR WIRELESS SIGNALIHG.

APPLICATION FILED AUG. 25,1908.

Patented Apr. 13, 1909.

2 smms-snm 1.

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m M a W A. PESSENDEN. APPARATUS POE WIRELESS SIGNALING. APPLICATIONFILED AUG.25,1908.

918,307. Patented Apr. 13, 1909,

2 SHEETSr-SHEET 2.

' Jmvayafwn .driven by the storage battery 17 and having part of thisspecification Figurel shows an Grreatv difliculty has been experiencedin stationsequipped with the usual type of apvals, and even in the morenorthern climates is a set of differential gears attached to the shaftoi the governing motor 16 and to the UNI ED smarts-manna UFFIQE.

REGINALD A. FESSENDEN, OF BRAlWl BOOK, MASSACHUSETTS.

APPARATUS ron winnrinss SIGNALING.

To all whom it in (my concern: Be it known that I, REeInALD-A, FESSEN-DEN, a citizen of-the United States, residing at Brant Rock, in theState of Massa chnsetts, have invented-certain new and. useful Apparatusfor Wireless Signaling, of which the following is afspecification; Thisinvention relates to electric signal 1ng, and especially to means forthe prevention of atmospheric and other disturbances, .which is itsprimaryobject. i

.In the accompanyingdrawings forming a arrangement of apparatus forcarrying out my invention, Fig. 2'sh'ows a detail of a governing device,Fig. 3, shows an arrangement of-circuits for use in sending and Fig.4 anarrangement of circuits for use in receiving.

wireless signaling on account of electric disturbances, moreparticularly atmospheric, CllStUl'bflIlCGS- In the tropics, for example,

paratus as a rule are unable to work at all tor months at a time, exceptat brief interthe same difliculties occur during the summer months. Bymy apparatus herein describethl succeed in overcoming thcldiiiilcultiesmet with'i'rom disturbances and more particularly such atmosphericdisturbances.

In Fig. 1,11 represents a steam turbine, 12 a throttle valve 'in thesteam pipe leading to the steanr turbine, 13 a governing valve operatedby the electric contact device 14. An alternating current dynamo 1'5,havinga frequency higher than the usual commercial frequencies but of afrequency sufliciently low to be'well within theliniitsof -a.udibil--ity, is driven by this turbine. (For example, a frequency of 900 issuitable for the dynamo.) 16 i. a continuous current motor its speedregulated by the .rhcostat 18. The speed of thismotor is governed by thevibrator reed 15) which makes and breaks the localicircuit containingthe battery 20, magnet 21 and a coil woundon thearmature of the motor l6and connected to thebrushes- R and 9, the rate of vibration beingaltered at will by shifting the weight- 1'9 on the reed. This method ofgoverning, known as the'lVadsworth method, is'well known. :22

Specification of Letters Patent. Application filed August 25,

. the view of F ig.

when the key Patented April 13, 1909. 1903. Serial No. 450,163.

shaft of the turbine 11 so that if the speed of the turbine varies fromthat of the governing motor 16, the arm carrying the contact brushes 24,25. will be carried forward or backward and make .contact with thecontact 26 or the contact 27, thereby operating the valve 13 by means ofthe current frorn'the battery 28 flowing through the magnet coils 29 and30, when the contacts 26, 24 or 25, 27 respectively are closedr (In 1the contacts are shown turned 90 out ofnorn'ial position, to show thearrzngement clearly.)

In Fig. 2 is shown an alternative form of regulator-for use in place ofmaking the contacts 24, 26 and 25, 27. In this the arm 23 of Fig. loperates by the lever 31 to produce a. pressure on the carbon plates 32,33-and thereby vary the current in the magnets 29, 30, respectively, andthus regulate valve 13.

I show a suitable circuit for signaling in Fig.- 8, where 34 shows asource of voltage, for example an alternating current dynamo giving avoltage of 25,000 volts at a frequency of 500 periods per second, or thedynamo of Fig. 1 being used. 35 is a capacity which may consist ofcompressed air condensers. 36 is an adjustable inductance which mayconsist of a straight piece oi:'=

copper wire, and a sliding contact'as shown. 37 1s a spark gap and-3S isan antenna groundedat 39. 40 is a movable contact arm so arranged as to.connect with the contacts '41 and 42 according as the. key 43-1depressed or not, the key 4:3.a'ctuating the movable arm e0 by means ofthe magnet/ ie encrgired by .the local battery 45, 46 being a spring forthe purpose of holding the movable co-itact arm 40 normally against'con-.

tact. .41.. In this method of operating the spark passes continuouslywhether signals are being sent or not, the frequency of the si nalsemitted being different when the key. 4-3 is depressed from thatobtaining is in. the normal position.

Fig. 4 shows a form of receiving device especially adapted for this workand form-' ing an interference preventer. In this an 4 antenna 47 of anysuitable type is grounded at GT, and {lSis a variable inductance, and 49a variable capacity in circuit with it. 5.0, 51 are primaries, and 52,.53 thesecondaries of variable transformers; These secondaries areconnected-to the primaries 54 and 55 of .a' second set of variabletransformers with and the circuit 52, 54:, 56 are preferably I tuned.

' measured by shunt on the telephone, of equal I alternator having afrequency of 70,000, in

above the normal frequencies used for altering generated by dynamo ofapproximately spark frequency of 900 per second, when at a secondaries58 and 59, the variable condensers 56 and 57 being connected in circuitI as shown. The secondaries 58, 59, of thel second pair of variabletransformers are connected so as to oppose each other, while I thecondenser 60, preferably variable and the l receiver 61, are in serieswith these secondaries. 62 1s a potentiometer and 63, 64 I are telephonereceivers. ,65, 66, 68, 69 are variable condensers; but 'tcondensers 68,69 may be omitted. The whole forms 'a'type of interference preventer.

The circuit 47, 48, 49, 51, 6 6, 67 and the circuit 53, 55, 57 arepreferably tuned to the frequency which it ,is desired to receive andthe other circuit 17, a8, a9, 50, 65, 67

tuned to other frequencies; oscillations not in resonance divide equallybetween the two branches. The circuit 58, 60, 59, 61 may be tuned ornot, and preferably it is not In experimenting with a high frequencyorder to determine the integrating effect of certain types of receivers,it was noted by me that when the trains of waves were broken up intodifi'erentlengths, when the trains succeeded each other at a frequencynating current work, the signals became more distinct in the presence ofatmospheric disturbances. It was noted for example, that in a specificcase where it is impossible to determine whether the experimentalstation was sending or not when the sparks succceded each other at afrequency of 250 (be- 125 cycles'ptir seeond,) yet the signals could beeasily readwhen the spark frequency was raised to 900. I discovered andexperimentally determined that the main reason for this wasaphysiological phenomenon, e. that when the higher frequencies were beingused for, signaling the attention of the bearer was concentrated on thehigher notes to such an extent that the low noises made by atmosphericdisturbances ceased to affect the consciousness. On the other hand whenthe sparks were produced by alternating cur rents of the usual frequencyit was impossible to concentrate the hearing upon the signals. andreception could not be accomplished. This physiological effect was foundexperiment to be so marked that messages could be read with the greatestof easeat a spark frequency of 250 per second it is impossible to tellwhether the station was sending or not, although with the same settings,at a time when there is no atmospheric disturbances, both sets ofsignals were, as

strength.

other hand, the selectivity,

zine November,

Heretofore in the practice of the art,

where spark frequencies have been used as a means of obtainingselectivity, this has been done by depending upon mechanical seleetivityalone, without electrical tuning to the wave frequency or groupfrequency (as shown for example, by British Patent- 28, 955/96, toBrown, and later in Blondels U. S. Patent 7 83,923 tiled December 3rd,1900, page 1, lines- 33 to 37) or by the combination of tuningelectrically to the wave frequency and mechanically or electricallytnningto the group frequency; (seeFessenden U .-S. Patents 727 ,325filed June 2, 1900: and 706,741-2 filed June 6, 1902; also shown laterin v:Shoema-kers U. S. Patent 7 19,58, filed Oct.3, 1902, and Stone 767,982, filed November 25, 1903). In all the above cases, however, theselectivity was obtained through the use 'of; group frequencies bytuning the receiver mechanically or electrically, so that it. would onlyrespond to a given group freue'ncy. In the presentapplication, on the por freedom from disturbance, is :not obtained by mechanical orelectrical tuning to the group frequency of 1000 sparks per second, butphysiologically by making use of. the novel physiological eifectdiscovered by the applicant ,and described above, which discoveryhaslater been independently corroborated in a in the Philosophical M (2921-.1:

paper published 1907, by Lord Rayliegh, who L therein points out thatthis physiological discovery was contrary to what had thereto-' forebeen supposed to be the case.

It is. to be noted that where, as in applieants prior U. S. patent 727,331, 21, 1903, group or spark frequencies as high as 500 cycles persecond have been used in connection with mechanical or electrical tuningto the group frequencies, this did not involve the discovery or use ofthe present physiological method of selectivity, since, with themechanical or electrical group tuning already referred to, thedisturbing frequencies were already cut out, or else produced a note ofthe same frequency as-that to which the circuit was already tuned. Forexample, any irregular atmospheric disturbance which affected thereceiver would that to which the receiver was already tuned, in the sameway as random blows on. a tuning fork Wlll cause it tovlbrate at a filedMara particular definite periodicity, always giving the same note.

Any suitable means of obtaining the desired spark frequency may be used,as for example an alternating current dynamo having a frequency of 500cycles, as above referred to. While the receiver may also bemechanically tuned to the group frequency, this is not alwaysadvantageous, and moreover it is not part of the present invention,

I any prior patent. No;-Z27,325,fof YMay th,

phrase is intended to mean an indicatorpulses does not emit a nophysiologically elii'ninatingthe effect of disadapted to produceelectromagnetic Waves of definite wave frequency, in-groups havturbingimpulses comprising a generator adapted to produce electromagnetic waves'sion of said waves, andan auralreceiver at another station operativelyconnected to a 'si ve to the group frequency ofthe'transmitphysiologically eliminating the effect of dishaving beenalready shown and, claimed" in -.In describing the indicator asresonantly unresponsive to the group frequency, such which on beingafiected .by' aperiodic .im-

teof the group fre,

quency being used.

The receiver is preferably mechanically tuned as well aselectrically.The method herein set forth is claimed inmy co-pending parentapplication N 0. 381,732 filed July 1st, 1907, and is not hereinclaimed. Having thus described my invention and illust 'atcd its use,what I claim as new'and desire to secure by Letters Patent, is thefollowing; 1. .In wireless telegraphy', apparatus for turbing impulsescomprising a generator ing a definite group frequency higher than 250per second but below the upper limitof audibility, devices at thesending station for producing signals by controlling the e'mission ofsaid waves, and an indicator at another station operatively connected toa re ceiving antenna and resonantly unresponsive to thegroup frequencyof the transmitted waves when acted upon by aperiodic impulses.

2. In wireless telegraphy, apparatus for physiologically eliminating theeffect of disot' definite wavefrequencyfln groups having a definitegroup frequency" higher than pei" second--' but below the upper limit.of' audibility', devices atth e sendi'ng station for producing signalsby controlling the emisl receiving antenna and resonantly unrespontedwaves when acted upon by aperiodic impulses.

3.111 wireless telegraphy, apparatus for turbing impulses comprising agenerator, adapted to produce electromagnetic waves of definite wavefrequency, in groups having definite group frequency of approximately1000 per second, devices at the sending station for producing signalsbycontrolling the emission of said waves, and an indicator at anotherstation operatively connected to a receiving antenna and resonantlyunresponsive to the group frequency of the transmitted waves when acte lupon by aperiodic impulses.

1. In wireless telegraphy, apparatus for physiologically eliminating theeffect of disturbing impulses comprising 1 a generator adapted toproduce electromagnetic waves of definite wave frequency, in groupshaving a definite group frequency higher than 250 per second but belo-wthe upper limit of audibility, devices at the sending station forproducing signals by controlling the emission of said waves,'and areceiver at another station operatively connected to a receiving antennaand resonantly unresponsive to the group frequency of the transmittedwaves when acted upon by aperiodic impulses, said receiver beingconnected in a circuit electrically tuned to the wave, frequency of thegenerated impulses.

5. In Wireless telegraphy, apparatus for physiologically eliminatingtheeffect of disturbing impulses comprising a generator adapted toproduce electromagnetic waves of definite wave frequency, in groupshaving a definite group frequency higher than 250 per second but belowthe upper limit of audibility, devices at the sending station forREGINALD A. rnssiiivnnn Witnesses Jnssm E. BENT, ADELEINE WOLEVE.

the effect on the re- ZEZMIEIR;

APP RATUS FOR WIRELESS JIBFJBULA ssenden, Brant Rock, Mass.

SIGNALING. Patent datsd April 13, 1909. Disclaimer filed February 25,1916,-

czlsey M. Bafiett, receivers for the asslgnee, National T that part, ofsaid specificationsat page 3, lines 10 and 11, which is in the Therecei'v er is preferably mechanically tuned as Well as electrically J iM w m n a N Am p as m 7 i .1 L W m w m m m w m a n s 1 w 76 m S a d w MS ,s r M R m l c m o G w m t w a 7 w m n m 0 y b .1 1 0 .l 9 fBQMWRHZEES 22E 5 EE QW

